More than 1,200 patients from 600 families with hereditary retinitis pigmentosa and allied diseases are on file; research is proposed to try to understand the pathogenetic mechanisms in these retinal diseases. An eye donor program has been started to study post mortem tissue from affected patients with a multidisciplined approach. Projects proposed include electron microscopic studies to define structural abnormalities, tissue culture of the pigment epithelium to see if processes of phagocytosis are abnormal, biochemical studies of remaining photoreceptors to see if phospholipid or protein synthesis are disturbed, and biochemical studies of pigment epithelium to see if lipofuscin accumulation is abnormal. Parallel studies on normal human eye donor tissue will also be conducted. Focal cone electroretinograms from different retinal areas will be recorded from patients representing each genetic type. Storage of all patient data on file in a computer will be done to allow efficient retrieval of information for cross correlations, to improve classification of both typical and a typical forms of these diseases, and to study factors that may affect the natural history of these diseases. Observations in post mortem tissue will be correlated with clinical and electroretinographic findings in donors prior to death and also compared with findings in living, affected relatives of donors and in patients on file with the same types of retinitis pigmentosa and allied diseases.